AT least 40 people have been killed by a major earthquake near the Iran-Pakistan border, according to reports, as officals warn they fear the death toll could climb significantly higher.

Office workers stand outside of their buildings following an earthquake tremor in Pakistan

The 7.8 magnitude earthquake struck Iran near the border with Pakistan, while tremors were felt as far across as India and the Gulf states.

Tall buildings shook in India's capital New Delhi – sending people running into the streets, witnesses said – while people were also evacuated from swaying offices and homes in Qatar and Dubai, according to reports.

An Iranian government official has said he anticipates hundreds will have died as a result of the quake, warning "it was the biggest earthquake in Iran in 40 years.

"We are expecting hundreds of dead," said the official, who spoke on condition of anonymity.

The U.S. Geological Survey said the huge quake hit at a depth of 15.2 km (9.4 miles), while the epicenter was in southeast Iran in an area of mountains and desert.

It was located 201 km (125 miles) southeast of the Iranian city of Zahedan and 250 km northwest of Turbat in Pakistan, reports said.

The quake struck less than a week after a powerful 6.3 magnitude quake struck close to Iran's only nuclear power station on April 9, killing 37 people and injuring 850 as it destroyed homes and devastated two villages.

Most of Iran's nuclear-related facilities are located in central Iran or its west, including the Bushehr nuclear power plant on the Gulf coast.

A U.S. Institute for Science and International Security map did not show any nuclear-linked facilities in southeastern Iran close to Pakistan.